At La Mar, Peru and Chile’s cross-border rivalry is forgotten, at least for a short time, with meals of spirited and high-caliber Peruvian cuisine. Chef Gaston Acurio’s empire spans the globe, delivering ceviche, causa (a layered potato dish), and tacu tacu (rice and beans) to hungry but discerning diners in Peru, Chile, Colombia, Ecuador, Venezuela, Spain, Mexico, Argentina, and soon New York. Chef Alexander Dioses leads the team at this Santiago outpost, where he serves big plates of bright and comforting Peruvian favors. The potatoes at La Mar are laced with smoky aji amarillo. The tres leches is spiked with pisco, and the seafood comes raw and marinated in “tiger’s milk” or grilled and tangled in saffron-tinted rice. The dishes may not have Chilean heritage, but no one in Santiago is complaining.